Recently, a game device with a characteristic controller has been introduced to the market and attracted popularity. One example is a controller that enables a player to perform an intuitive operation while holding the controller with one hand. Such a controller is wirelessly connected to a game device (main unit) and is capable of detecting a motion performed by moving the controller itself as well as a key operation (a button operation) performed by a player on the controller. For example, a player can play a shooting and the like by pointing a tip of a controller at a screen (a television or the like), aiming at a desired object (a target or the like) displayed on the screen, and then pressing a trigger button.
An invention of game device with such a controller has been disclosed that is capable of appropriately correcting a sighting position specified by the controller on a screen (refer to Patent Literature 1, for example).